JPH0340519Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spindle drive device equipped with two high-speed and low-speed drive motors for use in precision lathes and the like.

[Prior art]

This type of spindle drive device is configured to selectively rotate the spindle supported by the spindle head using an AC motor for high-speed drive and a DC servo motor for low-speed drive. For normal turning of outer diameters and end faces, the main shaft is rotated by a high-speed AC motor, and for turning that requires high precision, such as for lead grooves, a DC servo motor with low speed and small rotational fluctuations is used to drive the main shaft. It's driving. Thus, the rotation of each motor is transmitted to two electromagnetic clutches provided on the main shaft through belt transmissions, etc., and each motor is selectively connected to the main shaft by the electromagnetic clutches.

[Problem that the invention attempts to solve]

These conventional technologies each have two electromagnetic clutches and a transmission device, and the rotation of the AC motor or DC servo motor is transmitted to the main shaft through these, which makes the power transmission mechanism complicated. There was a problem. The present invention aims to solve these problems by improving the power transmission mechanism, further increasing machining accuracy and shortening machining time.

[Means to solve the problem]

For this purpose, the main shaft drive device according to the present invention, as shown in the drawings, selectively rotates a main shaft 20 supported on a main spindle head 10 by an AC motor 30 for high speed drive and a DC servo motor 40 for low speed drive. In the drive device, a stator 31 of the AC motor 30 having a rotor 32 fixed to the rear side of the main shaft head 10 and fixed to the main shaft 20 is connected to the main shaft 2.
Main shaft motor casing 12 coaxially supported with 0
a holding case 13 having a hollow shaft portion 13a attached to the main shaft motor casing 12 and protruding rearward coaxially with the main shaft 20; and a rotating body coaxially supported with the main shaft 20 in the hollow portion 13a. 65, and a rotation detector 35 that is provided in the internal space of the holding case 13 between the AC motor 30 and the rotating body 65 and detects the number of rotations of the main shaft 20.
, a DC servo motor 40 arranged parallel to the AC motor 30, and this DC servo motor 40.
a transmission device 60 consisting of a driving pulley 61 fixed to the output shaft of the main shaft 20, a driven pulley 63 provided on the rotary body 65, and a transmission belt 62 stretched between the two pulleys; and the hollow shaft of the main shaft 20. Part 13a
A boss 66 fixed to a part that projects further in the direction
It is characterized by comprising an electromagnetic clutch 50 which is provided between the rotating body 65 and the boss 66 and connects and disconnects them.

[Effect]

In the high-speed rotation state, the electromagnetic clutch 50 is disengaged, the main shaft 20 is separated from the DC servo motor 40, and is directly driven to high-speed rotation by the AC motor 30. The rotation of the main shaft 20 in this case is detected by the rotation detector 35 and the rotation speed is controlled.
In the low speed rotation state, the electromagnetic clutch 50 is engaged, and the main shaft 20 is driven to rotate at a low speed by the DC servo motor 40 via the transmission device 60. In this state, the rotor 32 of the AC motor 30 rotates at a low speed together with the main shaft, but there is almost no reaction between it and the stator 31, and the driven pulley 63 of the transmission device 60 is supported by the hollow shaft portion 13a. Therefore, the tension of the transmission belt 62 is not applied to the main shaft 20.

[Effect of idea]

According to the present invention, the rotor of the AC motor is directly fixed to the main shaft and drives the main shaft, so there is only one set of electromagnetic clutch and transmission device used for the DC servo motor, and the power transmission mechanism is simplified.
Costs can be reduced, and since the inertial weight of the high-speed transmission section is reduced, the main shaft can be rotated at high speed in a short time, and machining time can be shortened.

In addition, in the case of high-speed rotation, the rotation of the main shaft is detected by a rotation detector, so it is possible to control the rotation of the main shaft to reduce fluctuations in rotation.On the other hand, in the case of low-speed rotation, the tension of the transmission belt is not applied to the main shaft. The rotation accuracy of the main spindle is improved, and the machining accuracy can be improved in any case.

Furthermore, by installing a rotation detector in the internal space of the holding case between the AC motor and the rotating body, maintenance and inspection of the AC motor and rotation detector can be easily performed by simply removing the holding case from the spindle motor casing. At the same time, the structure of this part becomes more compact. Further, by arranging the DC servo motor in parallel with the AC motor, the length of the main shaft can be shortened, and the main shaft drive device as a whole can be made more compact.

〔Example〕

Examples will be explained below with reference to the drawings. The spindle head 10 consists of a spindle head body 11, an AC motor casing 12, a holding case 13, and a cover 14.
Bearings 21 and 22 and a thrust bearing 23 fixed to the spindle head body 11 rotatably support the main shaft 20. Each bearing metal 21 connected to the main shaft 20,
Static pressure pockets 21a and 22a are formed on the inner circumferential surface of 22, and pressurized lubricating oil is supplied from pump P to each static pressure pocket 21a and 22a through throttles 61 and 61 and oil passage 60, respectively. spindle 20
is supported by static pressure. Further, static pressure pockets 22c and 23a are also formed on the side surfaces of the bearing metal 22 and the thrust bearing metal 23, which are connected to the flange portion 20a of the main shaft 20, and are pressurized by the pump P through the throttles 61 and 61 and the oil passage 60, respectively. The lubricating oil is supplied to support the main shaft 20 with static pressure in the axial direction. The lubricating oil from each static pressure pocket 21a, 22a, 22c, 23a is returned to the reservoir 63 from the oil path 62 via the recovery grooves 21b, 22b, 23b.

An AC motor 30 for high-speed driving is installed coaxially with the main shaft 20 in an AC motor casing 12 fixed to the rear side of the main shaft head body 11 . The AC motor 30 has a resolver 35 which is a kind of rotation detector provided between the holding case 13 and the main shaft 20.
The stator 31 of the AC motor 30 is fixed within the AC motor casing 12, and the rotor 32 is fixed to the main shaft 12.

The rear end portion of the main shaft 20 protrudes from the hollow shaft portion 13a formed at the rear portion of the holding case 13.
A rotary body 65 is coaxially supported on the main shaft 20 on the shaft 3a, a boss 66 is fixed to the rear end of the main shaft 20 axially opposite the rotary body 65, and an electromagnetic clutch is provided between the rotary body 65 and the boss 66. 50 are provided. The electromagnetic clutch 50 includes a fixed friction plate 51 fixed to a boss 66, a movable friction plate 52 attached so as to be movable in the axial direction with respect to the rotary body 65 via a leaf spring 53, but rotated together with the rotary body 65, and a movable friction plate 52 fixed to the boss 66. It consists of a solenoid 54 provided at 66. Normally, the movable friction plate 52 is separated from the fixed friction plate 51 by the leaf spring 53, and the rotating body 65 and boss 66 are separated, but when the solenoid 54 is energized, the movable friction plate 5 made of a magnetic material
2 is attracted and frictionally engaged with the fixed friction plate 51 to connect the rotating body 65 and the boss 66.

A low-speed drive DC servo motor 40 is provided on a bracket 19 protruding from the cover 14 of the spindle head 10 in parallel with the spindle 20. The rotation of the DC servo motor 40, which is subjected to feedback control by the tachometer generator 41 so as to eliminate fluctuations in the rotation speed, is transmitted to the rotating body 65 via the transmission device 60. The transmission device 60 consists of a drive pulley 61 fixed to the output shaft of the DC servo motor 40, a driven pulley 63 formed on the outer periphery of a rotating body 65, and a transmission belt 62 stretched between both pulleys 61, 61. It is configured.

During normal turning processing, power is supplied to the AC motor 30, and power supply to the DC servo motor 40 and electromagnetic clutch 50 is stopped. In this state, the main shaft 20 is directly driven to rotate at high speed by the AC motor 30, and the rotation of the main shaft 20 is detected by the resolver 35 and is feedback-controlled to a predetermined rotation speed. In addition, a DC servo motor 40 and a transmission device 6
0 is separated by an electromagnetic clutch 50,
Since the transmission belt 62 is not driven, the inertial weight of the high-speed transmission section is reduced, and therefore the main shaft 20
Since the machine can reach high speed rotation in a short time, machining time can be shortened. When turning requires high precision, a DC servo motor 40 and an electromagnetic clutch 50 are used.
The AC motor 30 is supplied with power, and the supply of power to the AC motor 30 is stopped.
In this state, the main shaft 20 is connected to the pair of pulleys 61, 6.
3 and a transmission device 60 consisting of a transmission belt 62, a rotating body 65 on which a driven pulley 63 is formed, and a boss 66.
It is rotated at low speed by a DC servo motor 40 with little rotational fluctuation via an electromagnetic clutch 50 provided between the two. The driven pulley 63, which receives the tension of the transmission belt 62, is supported by the hollow shaft 13a of the holding case 13 fixed to the spindle head 10. Therefore, the tension of the transmission belt 62 is transferred to the spindle head 10 through the holding case 13. Since it is not received and applied to the main spindle 20, the rotation accuracy of the main spindle 20 is improved, and the processing accuracy is further improved. As described above, since only one set of electromagnetic clutch 50 and transmission device 60 is used for driving by DC servo motor 40, the power transmission mechanism is simple. In addition, in a low-speed rotation state, the rotor 32 of the AC motor 30 is connected to the main shaft 2.
0, but since the rotational speed is low, almost no reaction occurs with the stator 31, and since the speed is low, the transmission belt 62 does not vibrate.

Furthermore, since the resolver 35 is provided in the internal space of the holding case 13 between the AC motor 30 and the rotating body 65, the structure of this part becomes compact, and when the holding case 13 is removed from the spindle motor casing 12, the AC motor 30 Also, maintenance and inspection of the resolver 35 can be easily performed. Furthermore, since the DC servo motor 40 is arranged parallel to the AC motor 30, the axial length of the main shaft 20 is shortened, thereby making the main shaft drive device more compact as a whole.

In this embodiment, the fixed friction plate 51 and solenoid 54 of the electromagnetic clutch 50 are provided on the boss 66 side, but these 51 and 54 are provided on the rotating body 65 side.
The movable friction plate 51 may be provided on the boss 66 side.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view showing an embodiment of the spindle drive device according to the present invention. Explanation of symbols, 10...Spindle head, 12...Spindle motor casing, 13...Holding case, 13a...Hollow shaft portion, 20...Spindle, 30...AC motor, 31...Stator, 32...Rotor, 35...Rotation detector (resolver) ), 40... DC servo motor, 50... Electromagnetic clutch, 60... Transmission device, 61... Drive pulley, 62
...Transmission belt, 63...Driven pulley, 65...Rotating body, 66...Boss.

Claims (1)

[Scope of utility model registration request] In a spindle drive device that selectively rotates a spindle supported on a spindle head by an AC motor for high-speed drive and a DC servo motor for low-speed drive, the rotor is fixed to the rear side of the spindle head and fixed to the spindle. a main shaft motor casing that supports the stator of the AC motor coaxially with the main shaft; a holding case having a hollow shaft portion attached to the main shaft motor casing and protruding rearward coaxially with the main shaft; and the hollow shaft. a rotating body coaxially supported on the main shaft in a part thereof; a rotation detector provided in an internal space of the holding case between the AC motor and the rotating body to detect the number of rotations of the main shaft; A power transmission system consisting of a DC servo motor arranged parallel to the DC servo motor, a drive pulley fixed to the output shaft of the DC servo motor, a driven pulley provided on the rotating body, and a transmission belt stretched between both pulleys. The apparatus is characterized by comprising a device, a boss fixed to a portion of the main shaft that projects rearward from the hollow shaft portion, and an electromagnetic clutch provided between the rotating body and the boss to connect and disconnect the two. Main shaft drive.